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    <title>Execution commands of &mu;Csim</title>
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    <h2>Execution commands of <i>&mu;Csim</i></h2>
    <a name="run">
      <h3>r,run,go [start [stop]]</h3>
    </a>
    This command starts the execution of the simulated program.
    <p>Parameters are optional. First parameter specifies start address of
      the execution. By default execution starts at address specified by
      actual value of the PC. This can be overridden by first parameter.
    </p>
    <p>If second parameter is specified it places a dynamic breakpoint at
      specified address which stops the execution. If stop address is not
      given the simulator stops if it reaches a breakpoint, or the CPU
      accepts an interrupt and <b>stopit</b> option is TRUE, or fatal error
      occurs or <a href="#stop">stop</a> command is used on an other
      console, or ENTER key is pressed on the console where the run command
      was issued.
    </p>
    <p>If program execution is started the console is <i>frozen</i> it is
      not possible to give commands on this console to the simulator while
      execution is running. If it is needed to control the simulator during
      program execution then more consoles can be used. See using <a href="mulcons.html">multiple
        consoles</a> for more information.
    </p>
    <p>Note that first instruction is executed without effect of
      breakpoints and simulation will be started afterwards. It means that
      if there is a breakpoint at start address then it will not be hit. See
      following example:
    </p>
    <pre>$ <font color="#118811">./s51</font>
ucsim 0.2.38-pre1, Copyright (C) 1997 Daniel Drotos, Talker Bt.
ucsim comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
&gt; <font color="#118811">b 0x10</font>
Breakpoint 1 at 0x000010: MOV   R7,A
&gt; <font color="#118811">b 0x20</font>
Breakpoint 2 at 0x000020: MOV   R7,A
&gt; <font color="#118811">run 0x10</font>
Warning: maybe not instruction at 0x000010
Simulation started, PC=0x000010
Stop at 0x000020: (104) Breakpoint
F 0x000020
&gt; 
</pre>
    <hr>
    <a name="stop">
      <h3>stop</h3>
    </a>
    This command stops the simulation, it freezes the CPU and all the
    peripherals.
    <pre>$ <font color="#118811">s51 remoansi.hex</font>
ucsim 0.2.24, Copyright (C) 1997 Daniel Drotos, Talker Bt.
ucsim comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
58659 bytes read from remoansi.hex
&gt; <font color="#118811">g</font>
Simulation started
&gt; <font color="#118811">dr</font>
000000 00 01 00 14 00 00 5a 47 ......ZG
000000 00 .  ACC= 0x47  71 G  B= 0x01   DPTR= 0x001c @DPTR= 0x47  71 G
000001 01 .  PSW= 0x00 CY=0 AC=0 OV=0 P=0
   006f02 90 00 1e MOV   DPTR,#001e
&gt; <font color="#118811">stop</font>
   006ac5 24 a5    ADD   A,#a5
&gt; 
</pre>
    Simulated program is executed in background and the simulator accepts
    commands. If it stopped by the stop command the instruction pointed by
    PC is disassembled, see the <a href="#dis"><b>dis</b></a> command for
    description of disassembled form.
    <hr>
    <a name="step">
      <h3>s,step [steps]</h3>
    </a>
    Step command. It executes one instruction without effect of
    breakpoints.
    <p>The optional parameter can be used to specify number of instructions
      to execute. Note that breakpoints will stop the execution after the
      first instruction.
    </p>
    <pre>$ <font color="#118811">s51 remoansi.hex</font>
ucsim 0.2.12, Copyright (C) 1997 Daniel Drotos, Talker Bt.
ucsim comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
58659 bytes read from remoansi.hex
&gt; <font color="#118811">s</font>
000000 00 00 00 00 00 00 00 00 ........
000000 00 .  ACC= 0x00   0 .  B= 0x00   DPTR= 0x0000 @DPTR= 0x00   0 .
000000 00 .  PSW= 0x00 CY=0 AC=0 OV=0 P=0
   000160 c2 90    CLR   P1.0
&gt; </pre>
    After execution of actual instruction pointed by PC (or all
    instructions specified by the optional parameter) the <b>step</b>
    command dumps out the register set.
    <hr>
    <a name="n">
      <h3>n,next</h3>
    </a>
    Execute until next instruction is reached. This command is similar to
    <a href="#s"><b>step</b></a> command described above but if actual
    instruction to execute is a subroutine call the <b>next</b> command
    places a dynamic breakpoint after the call instruction and starts to
    execute the subroutine. If the subroutine is infinite the breakpoint
    set by <b>next</b> will never reached. It can be a dangerous situation
    because the execution started by the <b>next</b> command can not be
    stopped interactively. But it can be stopped by other breakpoints.
    <pre>$ <font color="#118811">s51 remoansi.hex</font>
ucsim 0.2.12, Copyright (C) 1997 Daniel Drotos, Talker Bt.
ucsim comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
58659 bytes read from remoansi.hex
&gt; <font color="#118811">run 0 0x172</font>
   000172 79 04    MOV   R1,#04
&gt; <font color="#118811">dis 0x172 0 5</font>
   000170 7f 00    MOV   R7,#00
   000172 79 04    MOV   R1,#04
   000174 12 0d b8 LCALL 0db8
   000177 0f       INC   R7
   000178 d9 fa    DJNZ  R1,0174
   00017a 75 0b 00 MOV   0b,#00
&gt; <font color="#118811">n</font>
000000 00 04 00 00 00 00 00 00 ........
000000 00 .  ACC= 0x00   0 .  B= 0x00   DPTR= 0x0000 @DPTR= 0x00   0 .
000004 00 .  PSW= 0x00 CY=0 AC=0 OV=0 P=0
   000174 12 0d b8 LCALL 0db8
&gt; <font color="#118811">n</font>
000000 00 04 00 00 00 00 00 00 ........
000000 00 .  ACC= 0x00   0 .  B= 0x00   DPTR= 0x0167 @DPTR= 0x00   0 .
000004 00 .  PSW= 0x00 CY=0 AC=0 OV=0 P=0
   000177 0f       INC   R7
&gt; </pre>
    <hr>
    <a name="pc">
      <h3>pc [address]</h3>
    </a>
    Using this command without any parameter it simply dumps out
    instruction pointed by the PC. Specify address if you want to set the
    PC.
    <pre>$ s51
S51 0.1.5, Copyright (C) 1997 Daniel Drotos, Talker Bt.
S51 comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
&gt; <font color="#118811">pc</font>
 * 000000 ff       MOV   R7,A
&gt; <font color="#118811">pc 123</font>
 * 00007b ff       MOV   R7,A
&gt; <font color="#118811">sopt debug t </font> 
&gt; <font color="#118811">pc 32</font>
Warning: maybe not instruction at 000020
 * 000020 ff       MOV   R7,A
&gt; </pre>
    <hr>

    
    <h3><a name="history">history</a></h3>
    
    History command can be used to inspect and manipulate history of
    executed instructions. It accepts following subcommands:

    <p><a href="#history_">history</a>
      <br>history <a href="#history_information">information</a>
      <br>history <a href="#history_list">list</a>
      <br>history <a href="#history_clear">clear</a>

      <blockquote>
	<h4><a name="history_">history</a></h4>
	This command (without a subcommand) prints out last 10
	elements of the command history in disassembled form.
	<pre>0&gt; <font color="#118811">hist</font>
 ? 0x0211 78          LD      A,B
 ? 0x0212 de 22       SBC     A,#0x22
 ? 0x0214 38 f7       JR      C,#-9
 ? 0x0216 c9          RET
 ? 0x0109 c3 04 02    JP      #0x0204
 ? 0x0204 3e 00       LD      A,#0x00
 ? 0x0206 cf          RST     8
 ? 0x0008 fb          EI
 ? 0x0009 ed 4d       RETI
 ? 0x0207 76          HALT
0&gt;
	</pre>

	<hr>
	<h4><a name="history_information">history information</a></h4>
	Print out information about execution history.

	<pre>0&gt; <font color="#118811">hist info</font>
len: 100
used: 100
insts: 100
0&gt;
	</pre>

	<b>Len</b> is size of the history, <b>used</b> shows how many
	slots are filled, <b>insts</b> is number of the instructions
	recorded by the history.

	<hr>
	<h4><a name="history_list">history list [nr]</a>
	<br>history print [nr]</h4>

	This command is the same as the <a href="#history_">history</a> command
	but it accepts a parameter which specifies how many records to
	print (defaults to 10):

	<pre>0&gt; <font color="#118811">hist list 3</font>
 ? 0x0008 fb          EI
 ? 0x0009 ed 4d       RETI
 ? 0x0207 76          HALT
0&gt; <font color="#118811">hist list 30</font>
 ? 0x020e 79          LD      A,C
 ? 0x020f d6 33       sub     #0x33
 ? 0x0211 78          LD      A,B
 ? 0x0212 de 22       SBC     A,#0x22
 ? 0x0214 38 f7       JR      C,#-9
 ? 0x020d 03          INC     BC
 ? 0x020e 79          LD      A,C
 ? 0x020f d6 33       sub     #0x33
 ? 0x0211 78          LD      A,B
 ? 0x0212 de 22       SBC     A,#0x22
 ? 0x0214 38 f7       JR      C,#-9
 ? 0x020d 03          INC     BC
 ? 0x020e 79          LD      A,C
 ? 0x020f d6 33       sub     #0x33
 ? 0x0211 78          LD      A,B
 ? 0x0212 de 22       SBC     A,#0x22
 ? 0x0214 38 f7       JR      C,#-9
 ? 0x020d 03          INC     BC
 ? 0x020e 79          LD      A,C
 ? 0x020f d6 33       sub     #0x33
 ? 0x0211 78          LD      A,B
 ? 0x0212 de 22       SBC     A,#0x22
 ? 0x0214 38 f7       JR      C,#-9
 ? 0x0216 c9          RET
 ? 0x0109 c3 04 02    JP      #0x0204
 ? 0x0204 3e 00       LD      A,#0x00
 ? 0x0206 cf          RST     8
 ? 0x0008 fb          EI
 ? 0x0009 ed 4d       RETI
 ? 0x0207 76          HALT
0&gt;
	</pre>

	<hr>
	<h4><a name="history_clear">history clear</a></h4>

	This command clears the history, it deletes all recorded elements.

	<pre>0&gt; <font color="#118811">hist list 3</font>
 ? 0x0008 fb          EI
 ? 0x0009 ed 4d       RETI
 ? 0x0207 76          HALT
0&gt; <font color="#118811">hist clear</font>
0&gt; <font color="#118811">hist info</font>
len: 100
used: 0
insts: 0
0&gt;
	</pre>
      </blockquote>
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